The log export industry in New Zealand and many other countries is required to count and barcode every log that is exported. After harvest, logs for export are typically delivered to a port on logging trucks or trailers. Upon arrival at the port, the load of logs on each truck is processed at a checkpoint or processing station. Typically, the number of logs in each load is counted and various measurements on each individual log are conducted to scale for volume and value, before being loaded onto ships for export.
Depending on the country, log scaling can be carried out according to various standards. In New Zealand, almost all logs exported are sold on volume based on the Japanese Agricultural Standard (JAS). Scaling for JAS volume typically involves measuring the small end diameter of each log and its length, and then calculating JAS volume based on these measurements. The log counting and scaling exercise is currently very labour intensive as it requires one or more log scalers per logging truck to count and scale each log manually. The log counting and scaling exercise can cause a bottleneck in the supply chain of the logs from the forest to the ship for export, or for supply to domestic customers.
To attempt to address the above issue, various automated systems have been proposed for assisting in automatic counting and measurement of logs. However, many of these currently proposed systems have various drawbacks which have limited their widespread adoption by the log export industry.
One such automated system is described in US patent application publication 2013/0144568. This system is a drive-through log measuring system for log loads on logging trucks. The system comprises a large structure mounting an array of lasers about its periphery and through which a logging truck may drive through. The system laser scans the log load on the back of the truck as it drives through and generates a 3D model of the log load. The 3D model is then processed to extract various characteristics of the logs, such as log diameters. This system is very large and expensive.
Another automated system for measuring logs is described in international PCT patent application publication WO 2005/080949. This system uses a stereo vision measuring unit mounted to a vehicle that is driven past a log pile on the ground and which captures stereo vision images of the log pile. The stereo images are then image processed to determine various physical properties of the logs, such as for measuring size and grading logs. This system requires a moving vehicle to move the measuring unit past the pile of logs situated on the ground and is not suited for measuring a log load in situ on a logging truck.
In this specification where reference has been made to patent specifications, other external documents, or other sources of information, this is generally for the purpose of providing a context for discussing the features of the invention. Unless specifically stated otherwise, reference to such external documents is not to be construed as an admission that such documents, or such sources of information, in any jurisdiction, are prior art, or form part of the common general knowledge in the art.